{8 (Acylcarbamoyl) thioacetyl{9 {0 cephalosporin derivatives

ABSTRACT

WHEREIN R is hydrogen, lower alkyl, phenyl-lower alkyl, tri(lower alkyl)silyl, a salt forming ion, or the group     ((Acylcarbamoyl)thioacetyl)cephalosporin derivatives of the formula R1 is hydrogen, lower alkyl, phenyl, thienyl or furyl; R2 is lower alkyl, lower alkoxy, phenyl or phenyl-lower alkyl; R3 is hydrogen, hydroxy or lower alkanoyloxy; R4 is lower alkyl, phenyl or phenyl-lower alkyl; and R5 is hydrogen or lower alkyl, are useful as antimicrobial agents.   D R A W I N G

United States Patent 91 Breuer et al.

[ Dec. 30, 1975 [(ACYLCARBAMOYL)THIOACETYL] CEPHALOSPORIN DERIVATIVES [75] Inventors: Hermann Breuer; Uwe D. Treuner,

both of Regensburg, Germany [73] Assignee: E. R. Squibb & Sons, Inc.,

Princeton, NJ.

[22] Filed: Aug. 8, 1974 [21] Appl. No.: 495,597

[52] US. CL... 260/243 C; 260/332.2 A; 260/347.2;

260/455 A [51] Int. Cl. C07D 501/28; A6lK 31/545 [58] Field of Search 260/243 C [56] References Cited OTHER PUBLICATIONS Gottstein et aL, J. Med. Chem., Vol. 14, No. 8, pp. 770-772 (1971).

Primary ExaminerDonald G. Daus Assistant ExaminerDiana G. Rivers Attorney, Agent, or F irm-Lawrence S. Levinson; Merle J. Smith [57] ABSTRACT [(Acylcarbamoyl)thioacetyl]cephalosporin derivatives of the formula I I I wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, tri(lower alkyl)silyl, a salt forming ion, or the group 13 Claims, No Drawings 1 2 [(ACYLCARBAMOYL) THIOACETYL] nesiumor an' amine salt in,ie.g., a (lower alkyl)amine CEPHALOSPORIN DERIVATIVES like methylamine ortriethylamine, etc. 1 l SUMMARY OF THE INVENTION The new [(acylcarbamoyDthroacetyllcephalosporm derivatives of this inve'ntion 'ai'e'produced by reacting a This invention relates to new [(acylcarbamoyl)thi- 5 7-aminocephalosporanic acid""compound [whi h i oacetyl]cephalosporanic derivatives of the formula l dcs 7-aminocc hal 'sfjoranic acid (7-ACA), 7-

o o R s e. w ll ii I R -C-NH-CS-CH CO NH- CH -CH CH /C a N\ /C-'CH R 0 C I C- OR R represents hydrogen, lower alkyl, phenyl-lower amino-3-desacetoxy-cephalosporanic acid (7-AD CA) alkyl, tri-(lower alkyl)silyl, a salt forming ion or the and other derivatives] of the formula group R represents hydrogen, lower alkyl, phenyl, thienyl or furyl; R represents lower alkyl, lower alkoxy, phenyl or phenyl-lower alkyl; R represents hydrogen, hydroxy or C N i c -CH R lower alkanoyloxy; R represents lower alkyl, phenyl or 2 3 phenyl-lower alkyl; and R is hydrogen or lower alkyl. 0 v c The preferred members within each group are as l follows: R is hydrogen, alkali metal, trimethylsilyl, benzhydryl or 40 v I I o O v CH2 O R, or derivative thereof, with an [(acylcarbamoyl)thio]acetic acid of the formula especially hydrogen, pivaloyloxy, sodium or potassium, (m) R CH COOH R, is hydrogen, lower alkyl or phenyl, especially hydrogen or phenyl; R is lower alkyl, especially methyl or S-C-NH-C-R, ethyl, or phenyl; R is hydrogen or acetoxy; and R is I I methyl or t-butyl.

or an acid halide or anhydride thereof The various groups represented by the Symbols h The derivatives of II referred to include, for example, the meanings defined below and these definitions are {h triethyl'afnine defivativei benzhydryl ester the retained throughout specificatio like. The acld Of is preferably the chloride.

The lower alkyl groups are the straight and branch d The reaction can also be carried out in the presence of chain hydrocarbon groups in the series from methylto dicyclohexylcarbodiimide the likeh l, h l d h l b i generally f d Th The reaction between the 7-aminocephalosporanic l w lk grqups are f h same type acid compound and the [(acylcarbamoyl)thio]acetic The lower alkanoyloxy groups represented by R acid is effected, for example, by dissolving or suspendinclude the acyl radicals of lower fatty acids containing g e tter r its acid chloride 01' anhydride in an alkyl radi als of th t pe d rib d ab v c inert organic solvent such as chloroform, tetrahydrofutoxy, propionoxy, butyrylc et acet y b ing pr ran, methylene chloride, dioxane, benzene or the like, ferred. and adding, at a reduced temperature of about 0 to The phenyl-lower alkyl radicals include a phenyl ring 20C about an equimolar amount of the 7-ACA or attached to a lower alkyl group of the kind described 7-ADCA compound, preferably in the presence of an above as well as those containing tw'o'phenyl groups activating compound such as dicyclohexylcarbodisuch as benzhydryl. H v I l imide; The product ofvthe reaction is then isolated by The salt forming ions represented byiR are metal conventional procedures,- e.g., by concentration or ions, e.g., alkali metal ions such as sodium or potasevaporation of the solvent. When the benzhydryl ester :sium, alkaline earth metal ions such as calcium or magis obtained, treatment of this product with trifluoroacetic and anisole yields the free carboxylic acid. Salts are produced in conventional manner by reaction with a base containing the desired cation.

A preferred method of producing the products of this invention comprises reacting approximately equimolar amounts of the 7-aminocephalosporanic acid compound of formula ll wherein R is benzhydryl and the acid of formula III in a solvent such as tetrahydrofuran at a temperature in the range of about to C in the presence of about an equimolar amount of dicyclohexylcarbodiimide. The dicyclohexylurea which is formed is filtered off and the product, which is the corresponding compound of formula I wherein R, R R and R represent the same groups as in the starting materials, is worked up from the filtrate by conventional procedures, e.g., concentration, crystallization, etc. The free acid, i.e. the product of formula I wherein R is hydrogen, is obtained by treating the benzhydryl ester with trifluoroacetic acid and anisole. Salts are obtained by treatment of the free acid with the appropriate basic material. For example, the potassium salt is obtained by the use of potassium ethylhexanoate or the sodium salt is obtained by the use of sodium bicarbonate.

A preferred alternate process comprises forming a mixed anhydride from the acid of formula III, for example by reaction with a chloroformate like isobutylchloroformate in the presence of N-methylmorpholine in a dry solvent like absolute tetrahydrofuran, and reacting this mixture anhydride with a 7-aminocephalosformula hal-CHOCOR,

wherein hal is halogen, preferably chlorine or bromine,

in an inert organic solvent such as dimethylformamide,

acetone, dioxane, benzene or the like, at about ambient temperature or below.

The [(acylcarbamoyl)thio]acetic acid of formula III is produced by reacting a mercaptoacetic acid of the formula with an isocyanate of the formula in the presence of an inorganic or organic base like an alkali metal hydroxide such as sodium hydroxide, or triethylamine or dimethylaniline or the like, in a solvent like methylene chloride.

Further process details are provided in the illustrative examples.

Certain of the compounds of this invention may exist in different optically active forms. The various stereoisomeric forms as well as the racemic mixtures are within the scope of the invention.

The compounds of this invention have a broad spectrum of antibacterial activity against both gram positive and gram negative organisms such as Staphylococcus aureus, Salmonella schottmuelleri, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli and Streptococcus pyogenes. They are used as antibacterial agents in a prophylactic manner, e.g., in cleaning or disinfecting compositions, or otherwise to combat infections due to organisms such as those named above, and in general can be utilized in a manner similar to cephradine and other cephalosporins. For example, a compound of formula I or a physiologically acceptable salt thereof can be used in various animal species in an amount of about 1 to mg./kg., daily, orally or parenterally, in single or two to four divided doses to treat infections of bacterial origin, e.g., 5.0 mg./kg. in mice.

Up to about 600 mg. of a compound of formula I or a physiologically acceptable salt thereof is incorporated in an oral dosage form such as tablets, capsules or elixirs or in a suppository or in an injectable form in a sterile aqueous vehicle prepared according to conventional pharmaceutical practice.

The following examples are illustrative of the invention. All temperatures are in degrees celsius. Additional variations are produced in the same manner by appropriate substitution in the starting material.

EXAMPLE 1 [(Benzoylcarbamoyl)thio]acetic acid EXAMPLE 2 3-[ (Acetyloxy)methyl]-7B-[ (benzoylamino)carbonyl thio]acetyl ]amino]-8-oxo-5 -thial -azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and potassium salt The mixed anhydride is formed from 1.6 gms. of [(benzoylcarbamoyl)thio]acetic acid, 0.93 ml. of isobutylchloroformate and 0.74 ml. of N-methylmorpholine in 40 ml. of absolute tetrahydrofuran at l 5.

The solution of the mixed anhydride is combined with an ice cold solution of 1.8 gms. of 7-aminocephalosporanic acid and 1.47 ml. of N-methylmorpholine in 30 ml. of 50% aqueous tetrahydrofuran. The solution is stirred for 1 hour at 5 and 1 hour at 0. The tetrahydrofuran is distilled off under vacuum. The aqueous solution is layered over with ethyl acetate and acidified. The ethyl acetate phase is concentrated and 2.3 gms. of crude product, 3-[(acetyloxy)methyl]-7B-[[[[(benzoylamino)carbonyl]thio]acetyl]amino]-8-oxo-S-thia- 1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid is isolated. The product is dissolved in methanol and potassium ethyl hexanoate'is added. Upon the addition of 5 ether, 3-[(acetyloxy)methyl]-7B-[[[[(benzoylamino)- carbonyl thio ]acetyl amino ]-8-oxo-5 -thia- 1 -azabic'yclo[4.2.0]octo-2-ene-2carboxylic acid, potassium salt, hydrate precipitates, m.p. l48l5 l (dec.).

EXAMPLE 3 3-[ (Acetyloxy)methyl]-7[3-[ (benzoylamino)carbonyl]thio]acetyl]amino]-8-oxo-thia-l-azabicyclo[4,2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester 2.87 gms. (0.012 mol.) of [(benzoylcarbamoyl)thio]acetic acid and 4.38 gms. (0.01 mol.) of 7- aminocephalosporanic acid diphenylmethyl ester are dissolved in 50 ml. of tetrahydrofuran and 2.27 gms. (0.01 1 mol.) of dicyclohexylcarbodiimide are added at 5. The mixture is stirred for 90 minutes at 5 and 90 minutes at room temperature. The mixture is then filtered, concentrated and ethyl acetate is added to the residue. 3.3 gms. of the product 3-[(acetyloxy)methyl]7B-[ [(benzoylamino)carbonyl ]thio]acetyl- ]amino]-8-oxo-5 -thial -azabicyclo[4. 2.0]oct-2-ene-2- carboxylic acid, diphenylmethyl ester, which is slightly soluble in ethyl acetate, is obtained, m.p. l62164. After recrystallization from methanol, the product melts at l65l67 (dec.).

EXAMPLE 4 3-[(Acetyloxy)methyl]-7[3-[ (benzoylamino)carbonyl ]thio]acetyl]amino]-8-oxo-5-thia- 1 -azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.

1.1 gms. of 3-[(acetyloxy)methyl]-7B-[[[[(benzoylamino)carbonyl]thio]acetyl]amino]-8-oxo-5-thia- 1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester, is added at 0 to 5 to a mixture of 20 ml. of trifluoroacetic acid and 6 ml. of anisole. The mixture is stirred for 10 minutes at room temperature, concentrated and treated with ether. 0.75 gms. of the product, 3-[(acetyloxy)methyl]7B-[{[[(benzoylamino)carbonyl]thio]acetyl]amino]-8-oxo-5-thial-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, is obtained, m.p. l62-l63 (dec.).

EXAMPLE 5 a-[[(Benzoylamino )carbonyl]thio]benzeneacetic acid 8.4 gms. (0.05 mol.) of a-phenylmercaptoacetic acid, 6.9 ml. (0.05 mol) of triethylamine and 7.4 gms. (0.05 mol.) of benzoyl isocyanate are reacted according to the procedure in Example 1. The product a- [[(benzoylamino)carbonyl]thio]benzeneacetic acid, is purified by recrystallization several times from methanol; yield 5.7 gms. m.p. l78-l80(dec.).

EXAMPLE 6 3-[(Acetyloxy)methyl]-7B-[ (benzoylamino )carbonyl]thio lphenylacetyl]amino]-8-oxo-5-thial azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester from ethyl acetate, the product melts at l80182 (dec.).

EXAMPLE 7 3-[(Acetyloxy)methyl]-7B-[ [(benzoylamino )carbonyl thio.]phenylacetyl amino -8-oxo-5 -thial azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid 1.8 gms. of 3-[( acetyloxy)methyl]-7B-[[[[(benzoylamino)carbonyl]thio]phenylacetyl]amino]-8-oxo- S-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester are treated with trifluoroacetic acid and anisole according to the procedure of Example 4 to obtain 1.4 gms. of 3-[(acetyloxy)methyl]-73- [[[[(benzoylamino )carbonyl]thio]phenylacetyl- ]amino]-8-oxo-5-thia-l -azabicyclo[4.2.0]oct-2-ene-2- carboxylic acid, m.p. 167l68 (dec.).

EXAMPLE 8 3-[ (Acetyloxy)methyl]-7B-['[ (benzoylamino )carbonyl]thio]phenylacetyl]amino]-8-oxo-5-thia-1- azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid disodium salt 592 mg. (0.001 mol.) of 3-[(acetyloxy)methyl]-7B- [[[[(benzoylamino)carbonyl]thio]pheny1acetyl- ]amino]-8-oxo-5-thia-l -azabicyclo[4.2.0 ]oct-2-ene-2- carboxylic acid are brought into solution in 200 ml. of water with 84 mg. of sodium bicarbonate and the solution is freeze dried to obtain 650 mg. of 3-[(acetyloxy)- methyl]-7B-[ [(benzoylamino )carbonyl]thio]- phenylacetyl]amino]-8-oxo-5-thial -azabicyclo[4.2 0]oct-2-ene-2-carboxylic acid disodium salt.

EXAMPLE 9 DL-a-[ (acetylamino )carbonyl]thio]benzeneacetic acid Equimolar proportions of a-phenylmercaptoacetic acid, acetyl isocyanate and triethylamine are reacted according to the procedure of Example 1 to obtain DL-a-[ acetylamino )carbonyl]thio]benzeneacetic acid which is recrystallized from ether, m.p. l53l 55 (dec.).

EXAMPLE 10 7,8-[ (Acetylamino )carbonyl1thio ]phenylacetyl- ]amino]-3-[(acetyloxy)methyl]-8-oxo-5-thia-lazabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,

diphenylmethyl ester 2.53 gms. (0.01 mol.) of DL-a-[[(acetylamino)carbonyl]thio]benzeneacetic acid, 3.64 gms. (0.0083 mol.) of 7-aminocephalosporanic acid, benzhydryl ester and 1.89 gms. (0.0092 mol.) of dicyclohexylcarbodiimide are reacted according to the procedure of Example 3 to obtain 5.5 gms. of crude 7B- [(acetylamino )carbonyl]thio]phenylacetyl]amino] 3-[(acetyloxy )methyl1-8-oxo-5-thia-l -azabicyclo[4.2 0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester. The product is purified by chromatography on a column of 500 gms. of Kieselg el (Merck). It is eluted with a mixture of toluene and ethylacetate (1:1). Fractions of about 40 ml. each are collected and subjected to thin layer chromatography. Fractions 38 to 65, which contain most of the desired product, are concentrated. The residue is treated with a little ethyl acetate. [[[[(acetylamino )carbonyl ]thio]phenylacetyl]amino]- 3- [(acetyloxy)methyl]-8-oxo-5 -thia-l -azabicy'clo[4.2.-

]oct-2-ene-2-carboxylic acid, diphenylmethyl ester crystallizes, m.p. l97199 (dec.).

EXAMPLE 1 l 7B-[ (Acetylamino )carbonyl]thio]phenylacetyl- ]amino]-3-[(acetyloxy)methyl]-8-0xo-5-thia-1- azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid 200 mg. of 7B-[[[[(acetylamino)carbonyl]thio]- phenylacetyl]amino]-3-[(acetyloxy)methyl]-8-oxo-5- thial -azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid diphenylmethyl ester are treated with 4 ml. of trifluorol5 acetic acid and 1.2 ml. of anisole. 120 mg. of the product, '7B-[ [(acetylamino )carbonyl]thio]phenylacetyl- ]amino]-3-[(acetyloxy)methyl]-8 oxo-5-thia-lazabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, are obtained, m.p. l53155 (dec.).

EXAMPLE 12 a-[ Ethoxycarbonyl )amino]carbonyl ]thi0]benzeneacetic acid a-phenylmercaptoacetic acid is reacted with ethoxy 3O carbonylisocyanate and triethylamine according to the procedure of Example 1 to obtain a-[[[(ethoxycarbonyl)amino]carbony1]thio]benzeneacetic acid, m.p.

129 (cyclohexane/benzene).

EXAMPLE 13 DL-3[ (acetyloxy)methyl]-7B-[ [(ethoxycarbonyl- )amino]carbonyl]thio ]phenylacetyl]amino]-8-oxo-5- thia- 1 -azabicyclo[4.2.0 ]oct-2-ene-2-carboxylic acid,

diphenylmethyl ester for 6 hours at 5. After filtering and concentrating the filtrate under vacuum, 5 gms of DL-3-[(acetyloxy)methyl]-7B-[ (ethoxycarbonyl)amino]carbonyl]thio]- phenylacetyl]amino]-8-oxo-5-thia-l-azabicyclo[4.2.-

0]oct-2-ene-2-carboxylic acid, diphenyl methyl ester are obtained as an oily residue.

EXAMPLE 14 DL-3-[(Acety1oxy)methy1]-7B-[[[[[(ethoxycarbony1- )amino]carbonyl]thio]phenylacetyl]amino]-8-oxo-5- thia-l -azabicyclo[4.2.0]oct-2ene-2-carboxylic acid DL-3-[(Acetyloxy)methyl]-7B-[ [(ethoxycarbonyl)amino]carbony1]thio]phenylacetyl]amino]-8- oxo-S-thial -azabicyclo[4.2.0 ]oct-2-ene-2-carboxylic acid diphenylmethyl ester is treated with trifluoroacetic acid and anisole according to the procedure of Example 4 and the product is precipitated from methylene chloride/carbon tetrachloride to obtain DL-3- [(acetyloxy)methyl]-7B-[ [(ethoxycarbonyl- )aminolcarbonyl]thio]phenylacetyl]amino]-8-oxo-5- thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid as a beige powder, m.p. 1 16.

EXAMPLE 15 DL-3-[(Acetyloxy )methyl]-7B-[ [(ethoxycarbonyl )amino]carbonyl]thio]phenylacetyl]amino]-8-oXo-5- thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,

potassium salt An aqueous solution containing equimolar amounts of DL-3-[ (acetyloxy)methyl]-7B-[ [(ethoxycarbonyl)amino]carbonyl]thio]phenylacetyl]amino]8- oxo-S-thia- 1 -azabicyclo[4.2.0 ]oct-2-ene-2-carboxylic acid and potassium bicarbonate is freeze dried to obtain DL-3-[ (acetyloxy )methyl]-7B-[[[[[(ethoxycarbonyl)amino]carbonyl]thio]phenylacetyl]amino]-8- oxo-S-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, potassium salt in the form of a white powder, m.p.

The following additional products are similarly obtained:

DL-7[3-[ methoxycarbonyl )amino]carbonyl- ]acetyl]amino]-3-(hydroxymethyl)-8-oxo-5-thia-1- azabicyclo[4.2.0]oct-2-ene-carboxylic acid.

DL-7B-[ [[[(n-butoxycarbonyl)amino]carbonyl]thio]phenylacetyl]amino-3-(hydroxymethyl)-8-oxo-5- thia-l-azabicyclo[4.2.0]oct-2-ene carboxylic acid.

DL-3-[(acetyloxymethyl]-7B-[ (benzyloxycarbonyl)amino]carbonyl]thio]pheny1acetyl]amino]-3- (hydroxymethy1)-8-oxo-5-thial -azabicyclo 4.2 .O]oct- 2-ene-2-carboxylic acid.

The following additional products having the formula (c) in the table are obtained by the procedure of Example 4 by substituting for the 7-aminocephalosporanic acid diphenylmethyl ester, the starting material (a),

and for the [(benzoylcarbamoyl)thio]acetic acid, the starting material (b) with the substituents indicated in the table:

-continued 5 H N r s R. H--COOH a -cH-co-NHcH-cH m 0 SC NH-C*R s c NH c R I I i ICI-OR g 2 C N C CH2 -R C-OR Example R R R:

36 H II 5 ll cH,c,,H H

37 K cH,c,,|-| ococH 38 H 1. -C,H -oc0ci-i 39 Na K} c,H H

What is claimed is: 1. A compound of the formula 0 oi: lllll wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenylmethyl, tri(lower alkyl)silyl,

alkali metal, alkaline earth metal, mono(lower alkyl)amine salt or tri(lower alkyl)amine salt; R is hydrogen, lower alkyl, phenyl, thienyl or furyl; R is lower alkyl,

2. A compound as in claim 1 wherein R is phenyl. 3. A compound as in claim 1 wherein R is hydrogen.

4. A compound as in claim 1 wherein R is phenyl or R is hydrogen, lower alkyl or phenyl; R is lower alkyl lower alkoxy, phenyl, phenyl-lower alkyl or diphenyl- 65 Or phenyl; R is hydrogen or acetoxy; and R is methyl methyl; R is hydrogen, hydroxy or lower alkanoyloxy; R is lower alkyl, phenyl, phenyl-lower alkyl or diphenylmethyl; and R is hydrogen or lower alkyl; said lower alkyl, lower alkoxy and lower alkanoyloxy groups having up to seven carbon atoms.

or t-butyl.

6. A compound as in claim 3 wherein R is hydrogen, R is phenyl and R is acetoxy.

7. A compound as in claim 2 wherein R is hydrogen, R is phenyl and R is lower alkanoyloxy.

13 14 8. A compound as in claim 3 wherein R is alkali 12. A compound as in claim 2whereinRis hydrogen, metal, R is phenyl and R is lower alkanoyloxy. R is lower alkoxy and R is lower alkanoyloxy.

9. A compound as in claim 2 wherein R is hydrogen; 13. A compound as in claim 12 wherein the lower R is phenyl and R is acetoxy.

10. A compound as in claim 2 wherein R is hydrogen, R is lower alkyl and R is lower alkanoyloxy.

11. A compound as in claim wherein the lower alkyl group is methyl and the lower alkanoyloxy group is acetoxy.

5 alkoxy group is ethoxy and the lower alkanoyloxy group is acetoxy. 

1. A COMPOUND OF THE FORMULA
 2. A compound as in claim 1 wherein R1 is phenyl.
 3. A compound as in claim 1 wherein R1 is hydrogen.
 4. A compound as in claim 1 wherein R2 is phenyl or lower alkyl.
 5. A compound as in claim 1 wherein R is hydrogen, alkali metal, trimethylsilyl, benzhydryl or
 6. A compound as in claim 3 wherein R is hydrogen, R2 is phenyl and R3 is acetoxy.
 7. A compound as in claim 2 wherein R is hydrogen, R2 is phenyl and R3 is lower alkanoyloxy.
 8. A compound as in claim 3 wherein R is alkali metal, R2 is phenyl and R3 is lower alkanoyloxy.
 9. A compound as in claim 2 wherein R is hydrogen; R2 is phenyl and R3 is acetoxy.
 10. A compound as in claim 2 wherein R is hydrogen, R2 is lower alkyl and R3 is lower alkanoyloxy.
 11. A compound as in claim 10 wherein the lower alkyl group is methyl and the lower alkanoyloxy group is acetoxy.
 12. A compound as in claim 2 wherein R is hydrogen, R2 is lower alkoxy and R3 is lower alkanoyloxy.
 13. A compound as in claim 12 wherein the lower alkoxy group is ethoxy and the lower alkanoyloxy group is acetoxy. 